1. Field of the Invention
The present invention relates to an anchor to be attached to various types of skeletons such as concrete buildings and structures, and a method of installing the anchor.
2. Background Art
In order to attach hanging objects such as air conditioners, lighting fixtures, and various types of pipes to an existing ceiling structure of a concrete building, for example, anchors to support the hanging objects are fixed to the ceiling structure. These anchors may be fixed not only to a ceiling structure but also to a wall surface or a floor. Conventionally known anchors of this type are disclosed for example in Japanese Patent Applications Laid-Open Nos. 10-231583 (1998) (patent literature 1) and 10-110475 (1998) (patent literature 2).
Referring for example to the anchor disclosed in patent literature 1, it includes a spreading sleeve, and a cone nut in the form of a truncated cone. The spreading sleeve is to be swaged to be integrated with a tip portion of a steel bar, and in which multiple slits extending in the axial direction from the tip of the spreading sleeve are provided. The cone nut has a smaller-diameter edge part press-fitted into a tip portion of the spreading sleeve. Regarding installation of this anchor, with the cone nut facing a hole in concrete, the anchor is inserted into the hole. Then, with the tip of the cone nut in abutting contact with the bottom of the hole, the steel bar is struck for example with a hammer to drive the anchor into the hole. This strike presses the cone nut into the spreading sleeve. In response to this press-fit, the tip portion of the spreading sleeve spreads outwardly and radially along a tapered surface of the cone nut to press the inner wall of the hole, thereby fixing the anchor to a skeleton.
Referring to the anchor disclosed in patent literature 2, it includes an anchor socket fixedly pressed-fitted into a hole in concrete, and an anchor bolt threaded into the anchor socket through an opening at one end portion of the anchor socket. A slit is formed in an opposite end portion of the anchor socket. A head is integrally provided at a tip portion of a shaft of the anchor bolt. The head is press-fitted into the inner circumference of the opposite end portion of the anchor socket to make the opposite end portion spread. Regarding installation of this anchor, with the opposite end portion of the anchor socket facing a hole in concrete, the anchor socket is inserted in advance into the hole. In this condition, the anchor bolt is threadedly inserted into the anchor socket through the opening at one end portion of the anchor socket. In response to the threaded insertion of the anchor bolt, the head at the tip portion of the anchor bolt makes the opposite end portion of the anchor socket spread, thereby fixing the anchor to a skeleton.